Strategic risk appraisal. Comparing expert- and literature-informed consequence assessments for environmental policy risks receiving national attention

Strategic risk appraisal (SRA) has been applied to compare diverse policy level risks to and from the environment in England and Wales. Its application has relied on expert-informed assessments of the potential consequences from residual risks that attract policy attention at the national scale. Here we compare consequence assessments, across environmental, economic and social impact categories that draw on ‘expert’- and ‘literature-based’ analyses of the evidence for 12 public risks appraised by Government. For environmental consequences there is reasonable agreement between the two sources of assessment, with expert-informed assessments providing a narrower dispersion of impact severity and with median values similar in scale to those produced by an analysis of the literature. The situation is more complex for economic consequences, with a greater spread in the median values, less consistency between the two assessment types and a shift toward higher severity values across the risk portfolio. For social consequences, the spread of severity values is greater still, with no consistent trend between the severities of impact expressed by the two types of assessment. For the latter, the findings suggest the need for a fuller representation of socioeconomic expertise in SRA and the workshops that inform SRA output

Twenty Years of the Polyvinyl Chloride Sustainability Challenges

Intense campaigning pressure on the UK PVC sector up to the late 1990s forced strategic engagement with sustainable development. Simplified outcomes from a detailed, consensus-based analysis by science-based NGO The Natural Step (TNS) took the form of five TNS Sustainability Challenges for PVC published in 2000. UK manufacturing companies initially used these Challenges to direct strategic progress. The Challenges have since been progressively taken up across European PVC value chains. The VinylPlus® programme uses an updated version of the five Challenges as a basis for voluntary commitments and transparent auditing of progress against published targets. Initial framing of the five TNS Sustainability Challenges for PVC were drafted consciously for generic relevance to other materials. Assessing the sustainability performance of some alternative materials to PVC against the five Sustainability Challenges reveals different sustainability performance in a range of potential applications. This highlights the danger inherent in automatic selection or deselection of materials in the absence of assessment of options on a ‘level playing field’ of sustainability principles. The five TNS Sustainability Challenges for PVC remain valid today and into the longer-term future as a basis for making stepwise, profitable progress towards the goal of sustainability for PVC and other materials

Contaminant issues in production and application of biochar

For widespread use of biochar in agriculture and horticulture, it must be ensured that application will neither adversely affect soil and plants, nor exceed legislated contaminant concentrations. The most relevant groups of contaminants in biochar are potentially toxic elements (PTEs), polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOC). In this thesis, the concentrations of these groups of contaminants were analysed in 90 different biochars produced by slow pyrolysis. Subsequently, the concentrations were compared to legislation/guideline threshold values and linked to production conditions. The risk these contaminants pose to plant growth was also assessed, to give recommendations on production of safe biochar. PTEs can neither be formed nor destroyed, which means their presence in biochar is predominantly determined by feedstock type. However, significant levels of Cr, Fe and Ni were introduced into biochar from the furnace steel, whilst PTEs with low boiling points, such as As, Cd and Zn, partially evaporated during pyrolysis. PTEs were not responsible for phytotoxic effects observed for PTE-rich biochars despite biochar’s exceedance of available and total PTE threshold values for soil and soil amendments. Although initial tests were promising, the risk that PTE-rich biochars as amendment for soil and growing media pose, needs further investigation. The PAH concentration in biochar was markedly reduced by increasing carrier gas flow rate, and the type of feedstock also influenced the PAH content. However, there was no clear dependence of pyrolysis temperature on PAH concentrations, which was attributed to PAHs being increasingly formed and evaporated at higher pyrolysis temperatures. Ultimately, condensation of pyrolysis vapours and deposition on biochar was identified as the main risk for biochar contamination with PAHs, as this resulted in elevated concentrations of high-risk, higher molecular weight PAHs. Weaknesses in the pyrolysis unit design, such as cold zones, resulted in elevated concentrations of VOCs, as well as PAHs, in biochar. Comparing concentrations and phytotoxic potential of both compound groups, it was concluded that observed toxic effects were much more likely caused by VOCs in biochars containing both contaminants. Overall, formation of VOCs and PAHs cannot be prevented, but their presence in biochar resulting from retention and deposition can be minimised

The sources, impact and management of car park runoff pollution: a review

Traffic emissions contribute significantly to the build-up of diffuse pollution loads on urban surfaces with their subsequent mobilisation and direct discharge posing problems for receiving water quality. This review focuses on the impact and mitigation of solids, metals, nutrients and organic pollutants in the runoff deriving from car parks. Variabilities in the discharged pollutant levels and in the potentials for pollutant mitigation complicate an impact assessment of car park runoff. The different available stormwater best management practices and proprietary devices are reported to be capable of reductions of between 20% and almost 100% for both suspended solids and a range of metals. This review contributes to prioritising the treatment options which can achieve the appropriate pollutant reductions whilst conforming to the site requirements of a typical car park. By applying different treatment scenarios to the runoff from a hypothetical car park, it is shown that optimal performance, in terms of ecological benefits for the receiving water, can be achieved using a treatment train incorporating permeable paving and bioretention systems. The review identifies existing research gaps and emphasises the pertinent management practices as well as design issues which are relevant to the mitigation of car park pollution

Concept for the Evaluation of Carcinogenic Substances in Population-Based Human Biomonitoring

The Human Biomonitoring (HBM) Commission at the German Environment Agency holds the opinion that for environmental carcinogens for which no exposure levels can be assumed and are harmless to health, health-based guidance values corresponding to the classical definition of the HBM-I or HBM-II value cannot be established. Therefore, only reference values have been derived so far for genotoxic carcinogens from exposure data of the general population or subpopulations. The concept presented here opens up the possibility of performing health risk assessments of carcinogenic substances in human biomonitoring, and thus goes decisively beyond the purely descriptive statistical reference value concept. Using the presented method, quantitative dose descriptors of internal exposure can be derived from those of external exposure, provided that sufficient toxicokinetic information is available. Dose descriptors of internal exposure then allow the simple estimate of additional lifetime cancer risks for measured biomarker concentrations or, conversely, of equivalent concentrations for selected risks, such as those considered as tolerable for the general population. HBM data of chronic exposures to genotoxic carcinogens can thus be used to assess the additional lifetime cancer risk referring to the general population and to justify and prioritize risk management measures